1. Field of the Invention
The present invention relates to an improved lock structure, and especially to a lock structure which is more convenient in use and more difficult to be unlawfully unlocked by a thief, thus theft-proof effect can be enhanced.
2. Description of the Prior Art
Locks used in the markets presently are provided with rectangular key holes, the walls of the key holes are straight surfaces. Therefore, a thief can easily make a judgement according to the arranged pusher pins in the key holes with the straight surfaces and unlock with a master key. In this way, locks are subjected to loss of their theft-proof effect.
Conventional locks in the markets can only permit a key to be drawn out of it by rotating of the key to a predetermined position no matter in locking or unlocking by means of the serrated shape on one edge of the key which mates with the pusher pins. When the key is rotated from the predetermined position, the pusher pins can not be retreated and block the key from drawing out, and inconvenience of use can be resulted.